The overall objective of this project is to develop a microporous tracheal prosthesis that will be permanently bioincorporated by the host and lined with epithelium. It will be fabricated from negative replications of the naturally occurring microporous exoskeletons of coral and sea urchins in biomedical polymers. The completely interconnecting porosity of relatively uniform diameter is rapidly ingrown by mammalian soft tissue perhaps by providing support and direction to a basic unit of regenerating soft tissue. The project will be divided into three simultaneous, interrelating phases. The biology of ingrowth will be studied by implanting porous test cylinders. The influence of primary variables (polymer and pore characteristics) and secondary variables (site of implantation, biodegradable porous phase filler, antibiotic dispersion in polymer and "wrapping") on ingrowth will be evaluated quantitatively and qualitatively in the dog and rabbit. Favorable combinations of variables will then be tested as 3 cm prostheses in the thoracic trachea of the dog for 1 to 2 months, following the progress of healing by bronchoscopy with biopsy. Finally, those designs that show excellent healing by 1 to 2 months will undergo long term evaluation in 8 cm lengths.